Although defects in chemotaxis of polymorphonuclear leukocytes (PMNs) are reported in many disease states, except for children in whom such defects aid in diagnosing a few rare immunodeficiency states, measurements of chemotaxis are of minimal importance in clinical medicine. One reason of this lack of clinical utility is the absence of a test precisely quantitating PMN motility in an individual patient. Since chemotaxis is a major factor in PMN function, precise measurements of cell motility should offer information of value in managing patients. The aim of this application is to determine if a newly developed computer-assisted video microscopic system for direct testing of PMN motility provides precise, reproducible and clinically meaningful measurements of chemotaxis and chemokinesis in various clinical states. This system videotapes microscopically observed PMNs in a chamber in which the cells are subjected to a gradient of chemoattractant (f-met-leu-phe). A computer analyzes the videotape images for cell speed and direction. As many as 50 cells are tracked simultaneously at time intervals as brief as 10 seconds. Using this system, chemotaxis and chemokinesis will be measured for PMNs of 20 neonates, children, adults, and elderly individuals. These values will be compared with data obtained using the Boyden chamber assay. After determining the characteristics of PMNs in these populations, additional studies will be performed in patients with known PMN defects in chemotaxis due to severe combined immunodeficiency syndrome to assess the utility of the computer-assisted video methods in detecting abnormalities. Patients with insulin requiring diabetes mellitus who are in poor control will also be studied to determine if defects in chemotaxis occur in this important population. The development of a reliable test for quantifying chemotactic abnormalities of PMNs should aid in detecting unsuspected abnormalities and in managing disease states in which impaired chemotaxis contributes to the illness.